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stb_ds: fix signed shift overflow in byte hashes #2024

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stb_ds: fix signed shift overflow in byte hashes #2024

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12 changes: 6 additions & 6 deletions stb_ds.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1079,8 +1079,8 @@ static size_t stbds_siphash_bytes(void *p, size_t len, size_t seed)
} while (0)

for (i=0; i+sizeof(size_t) <= len; i += sizeof(size_t), d += sizeof(size_t)) {
data = d[0] | (d[1] << 8) | (d[2] << 16) | (d[3] << 24);
data |= (size_t) (d[4] | (d[5] << 8) | (d[6] << 16) | (d[7] << 24)) << 16 << 16; // discarded if size_t == 4
data = d[0] | (d[1] << 8) | (d[2] << 16) | ((unsigned int) d[3] << 24);
data |= (size_t) (d[4] | (d[5] << 8) | (d[6] << 16) | ((unsigned int) d[7] << 24)) << 16 << 16; // discarded if size_t == 4

v3 ^= data;
for (j=0; j < STBDS_SIPHASH_C_ROUNDS; ++j)
Expand All @@ -1092,7 +1092,7 @@ static size_t stbds_siphash_bytes(void *p, size_t len, size_t seed)
case 7: data |= ((size_t) d[6] << 24) << 24; // fall through
case 6: data |= ((size_t) d[5] << 20) << 20; // fall through
case 5: data |= ((size_t) d[4] << 16) << 16; // fall through
case 4: data |= (d[3] << 24); // fall through
case 4: data |= ((unsigned int) d[3] << 24); // fall through
case 3: data |= (d[2] << 16); // fall through
case 2: data |= (d[1] << 8); // fall through
case 1: data |= d[0]; // fall through
Expand Down Expand Up @@ -1121,7 +1121,7 @@ size_t stbds_hash_bytes(void *p, size_t len, size_t seed)
unsigned char *d = (unsigned char *) p;

if (len == 4) {
unsigned int hash = d[0] | (d[1] << 8) | (d[2] << 16) | (d[3] << 24);
unsigned int hash = d[0] | (d[1] << 8) | (d[2] << 16) | ((unsigned int) d[3] << 24);
#if 0
// HASH32-A Bob Jenkin's hash function w/o large constants
hash ^= seed;
Expand Down Expand Up @@ -1177,8 +1177,8 @@ size_t stbds_hash_bytes(void *p, size_t len, size_t seed)

return (((size_t) hash << 16 << 16) | hash) ^ seed;
} else if (len == 8 && sizeof(size_t) == 8) {
size_t hash = d[0] | (d[1] << 8) | (d[2] << 16) | (d[3] << 24);
hash |= (size_t) (d[4] | (d[5] << 8) | (d[6] << 16) | (d[7] << 24)) << 16 << 16; // avoid warning if size_t == 4
size_t hash = d[0] | (d[1] << 8) | (d[2] << 16) | ((unsigned int) d[3] << 24);
hash |= (size_t) (d[4] | (d[5] << 8) | (d[6] << 16) | ((unsigned int) d[7] << 24)) << 16 << 16; // avoid warning if size_t == 4
hash ^= seed;
hash = (~hash) + (hash << 21);
hash ^= STBDS_ROTATE_RIGHT(hash,24);
Expand Down